Compounding right through a modern clear coat....

[TTQ B4U]

A fast cut microfiber pad and fat cut cream on a 21 with a 5 inch plate, no problem especially on an edge

^^ This. Have only messed up once on the edge of a door handle when using my 3401 with a microfiber pad. Should have known better but was in auto-pilot mode and didn't realize it was hitting so close. Now I use more care. Owner was fine with it and we touched it up with paint he had in the glove box.

[k20trick]

This is a major fear of many new and inexperienced detailer's everywhere. Is it justified? How easy (or hard) would it be to polish through a clear coat on your average modern car with a dual action polisher? Assume you are using any of the available over the counter compounds like ultimate compound, M105, Ice speed compound, ect,,,, and foam or microfiber pads.

Im no pro here, but it would have to take a lot to burn through, but that doesnt mean you should try it like I did. I've compounded one area multiple times and still no burn through. Actually the paint got better and better, not saying you should try this because Im sure it is risky. Luckily it was a beat up test panel with tons of scratches, rock chips, and cats clawing the hell out of it. It needs a repaint but I wanted to test to see how far I could go.

[AutowerxDetailing]

If you don't measure the paint, and if you aren't 99.9% positive you know the full history of the paint, then there is no way to know for sure how risky polishing a vehicle will be. Any machine, under the right set of circumstances, can burn though the paint.

[lawrenceSA]

How are all of you making statements about how hard or easy it would be to do, without knowing how thick the clear coat is to start with? We all know that modern clear coats seem to be getting thinner and thinner and whilst it is 'normal' for me to see around 150µ total paint thickness on most new VW's, there are other manufacturers where the film build is like 70µ out the factory... so it is a very 'unsafe' assumption to make that because its a new modern car, you have a certain clear coat thickness/life in the paint.

And even if you do own a PTG, its not a foolproof solution (unless you are dropping serious money on one which measures individual layers) because even though the total film build may be high (like with most repaints) you won't always know what each individual layer is doing.

If there is only a few microns of clear left, it will be super easy to strike through - I have a BMW bonnet in my garage that I use for testing and I struck through the clear in a section reading 250 odd microns - presumable there was a little clear on top of a bunch of primer/base/old paint? There are also sections on the same bonnet where I have sanded extensively and am picking up readings as low as 210µ and the clear is still in tact.

IMO the best advice I can give is

a) make sure you own a PTG if you are planning on doing any serious correction work (any more than say a finishing polish)
b) always perform a test spot to enable you to remove as little paint as possible whilst still getting the desired results and
c) apply some common sense to the PTG readings before, during and after your test spot(s) to decide on the best way forward and
d) always tape up body lines and panel edges where there is an increased risk of striking through.

[fightnews]

^^ This. Have only messed up once on the edge of a door handle when using my 3401 with a microfiber pad. Should have known better but was in auto-pilot mode and didn't realize it was hitting so close. Now I use more care. Owner was fine with it and we touched it up with paint he had in the glove box.

why did hitting the edge of the door make it burn or wear through the clearcoat?

[fightnews]

Im no pro here, but it would have to take a lot to burn through, but that doesnt mean you should try it like I did. I've compounded one area multiple times and still no burn through. Actually the paint got better and better, not saying you should try this because Im sure it is risky. Luckily it was a beat up test panel with tons of scratches, rock chips, and cats clawing the hell out of it. It needs a repaint but I wanted to test to see how far I could go.

oh nice my front bumper is like that lots of chips and needs repainting, when you say multiple times how many u talking? ten, twenty?

[fightnews]

How are all of you making statements about how hard or easy it would be to do, without knowing how thick the clear coat is to start with? We all know that modern clear coats seem to be getting thinner and thinner and whilst it is 'normal' for me to see around 150µ total paint thickness on most new VW's, there are other manufacturers where the film build is like 70µ out the factory... so it is a very 'unsafe' assumption to make that because its a new modern car, you have a certain clear coat thickness/life in the paint.

And even if you do own a PTG, its not a foolproof solution (unless you are dropping serious money on one which measures individual layers) because even though the total film build may be high (like with most repaints) you won't always know what each individual layer is doing.

If there is only a few microns of clear left, it will be super easy to strike through - I have a BMW bonnet in my garage that I use for testing and I struck through the clear in a section reading 250 odd microns - presumable there was a little clear on top of a bunch of primer/base/old paint? There are also sections on the same bonnet where I have sanded extensively and am picking up readings as low as 210µ and the clear is still in tact.

IMO the best advice I can give is

a) make sure you own a PTG if you are planning on doing any serious correction work (any more than say a finishing polish)
b) always perform a test spot to enable you to remove as little paint as possible whilst still getting the desired results and
c) apply some common sense to the PTG readings before, during and after your test spot(s) to decide on the best way forward and
d) always tape up body lines and panel edges where there is an increased risk of striking through.

thanks how many times did u compound it and or sand it before you struck through? also how can you tell when you have gone through it?

i understand you are a professional and i have a strong appreciation for doing things the right way. i just cant afford a gauge,i can afford it actually but im only working on my car. i could probably get the whole thing re painted for the price of a top quality gauge. maybe down the road, i do want to start detailing for money but i dont think i can do a car fast enough to make any real money, it takes me days to do my car nobodies going to pay me that kind of labor. i want to make at least fifty bucks an hour to make it worth it but it takes me two hours or more just to wash, dry, clay a car thats not even including dressing the tires and all that. im doing a full correction on my car and this is going to be my forth day working on it and its gonna take all day to finish, unless someone wants to pay me five thousand for a detail i dont see how i can make it work? its hard labor too

[lawrenceSA]

To be honest I can't recall exactly what I had done one that specific section prior to striking through.... but.... I think the more important lesson for me was that even when the PTG is giving you a supposedly 'healthy' paint reading, there is a risk of striking through the clear if you don't know EXACTLY how much clear you are working on (given that at 250'ish I struck through in 1 section, but at 210 in another section the clear is still in tact) - granted, this is on a repainted panel and I'd assume on a OEM panel the clear coat thickness and underlying layers will be more consistent in their 'thickness'???

But to measure individual layers the PTG is pricey - more than I as a weekend warrior (30 to 40 cars a year) can afford (especially over here with the exchange rate and shipping being as astronomical as they are) I am currently using a CEM-DT 156 (eBay) and so can only establish total film build, and have to 'guesstimate' the actual clear portion, but for the price, its a great little tool. It helps to give me an IDEA of how much clear is on the car, and then I can determine from my test spot(s) what is needed and how much that will remove, and can then make a more informed decision about whether compounding is a wise decision or not.

You will quickly see if you have struck through the clear and the color of the base coat with show up on your pads, and you will be left with a spot in your paint that is dull in comparison to the surrounding clear <--- I hope you don't ever have to find out firsthand what that looks/feels like.

Also just bear in mind that whilst we are all talking about getting to the point of actually striking THROUGH the clear, there has to be a point before you even get there where you have thinned out the clear enough that a) its no longer offering the UV protection it was intended to and/or b) you have 'voided' the OEM's warranty by removing too much clear [Bob aka FUNX650 will probably be able to quote you the specific allowances in terms of clear coat removal and warranties etc)


Edited to add: If you are working only on your own car, maybe you can find a detailer close to you who would be willing to measure you paint for you quickly, so you at least have some idea of what you are facing...?

[HateSwirls]

Depends on which DA.

My Rupes 15 really heats to the paint, very warm to the touch.
That being said one could when using a very harsh compound , very slow arm speed on a fine Sharp edge.
Chances of burning through is very, very low however.


Sent from my iPad using Autogeekonline mobile app

[lawrenceSA]

I think it may also be beneficial to distinguish between BURNING through the clear coat (due to excessive heat buildup) and STRIKING through the clear coat (due to too much paint removal).

To my mind anyway, burning through the paint will be way more difficult than striking through the clear.